FIELD OF THE INVENTION AND PRIOR ART
This invention relates to a method for measuring the velocity of water flow at a given point in a field of flow set up under a non-contact condition within a water flow model, i.e., a device for simulating fluid flow by observing flow in a water simulator or flow model.
This application is related to our copending application Ser. No. 550,005, filed Nov. 9, 1983.
Heretofore, for the measurement of the velocity in a water flow model, the method which makes use of a Pitot tube and the method of electric measurement which utilizes the phenomenon that the volume of electric current flowing through a sensor (formed of an electric wire) is varied in proportion as the volume of heat taken away from the sensor varies with the change in the velocity of flow have been available. These conventional methods for measurement of the velocity of flow inevitably necessitate installation of the Pitot tube and the sensor respectively within the fields of flow and, consequently, causes flow of water to flow in paths deviating from the paths which would naturally form if the Pitot tube and the sensor were not installed in the fields. The Pitot tube further is incapable of being installed in any narrow field of flow. This drawback applies also to the sensor which is used for the method of electric measurement because the sensor requires a steady support structure which is capable of resisting vibrations. Further in either of the methods of measurement under discussion, changes in the velocity of flow cannot be grasped in the form of numerical values displayed through the medium of any measuring instrument and can never be evaluated even roughly through visual observation. It is, of course, never possible for the momentary condition of the field of flow to be visually observed at the same time that the velocity of flow is measured.
The conventional methods available for the measurement of the velocity of a flow in the water flow model cannot provide accurate measurement of the velocity, because they have been unable to measure the velocity under a non-contact condition. In the field of flow which entails a reaction and a heat transfer such as, for example, the actual combustion, since the fluid expands and loses viscosity, it is not sufficient to graphically analyze the change in concentration. Unless the velocity is determined, the actual combustion cannot be accurately predicted. In this respect, it has been important and desirable as well for the velocity of a flow to be accurately measured in order that the water flow model may function as a faithful simulator of the actual phenomenon.